Maruyama Masao established the history of Japanese thought in 『A Study on the History of Political Thoughts in Japan』 with Ogyu Sorai as the center. Maruyama tried to find out how the orthodox world image of feudal society is internally collapsing, centering on the study of Sorai. Through the clarification of these tasks, it is to “examine the pattern of modernization of Japanese society and Japanese thought in a broad sense, and the characteristics of the West on the one hand and Asian countries on the other hand”. However, Maruyama's research on Sorai studies was not submitted through thorough reading of Sorai's writings, so he neglected to deal with the problems within the Sorai school. Sorai's historical evaluation of Dazai Shundai called 'Epigonen' will tell you that.